Doing this is bring the SID image in with the data connect then export to AutoCAD, this takes the image and converts it to pgn and Impression should be able to read that.
The sid file extension is most likely best known for its use for LizardTech MrSID image file format. MrSID is an acronym for Multi-resolution Seamless Image Database, a powerful wavelet-based image compressor, viewer and file format for massive raster images. These data can be viewed in a variety of GIS software applications.
MrSID is proprietary format owned by LizardTech, subsidiary of Celartem Technology Inc., a Japan-based technology company focused on storage and distribution technologies for digital images. MrSID file format is designed to enable portability of massive bit-mapped (raster) images. The format employs discrete wavelet transformations (DWT) in a seamless fashion on tile subsets of the image data and stores the wavelet coefficients in a data structure that supports efficient retrieval of the data needed to generate a specified rectangular zone of the image at a chosen spatial resolution. The data structure of a MrSID image is a set of bitplanes designed to support 'transactions' of image data by extracting and delivering exactly and only those bitplanes necessary to construct a view according to desired scene, scale, or image quality, independent of bandwidth constraints. The format was designed to enable instantaneous viewing and manipulation of imagery both locally and over networks without sacrificing quality. The format is intended for use in Geographic Information Systems (GIS) and satellite imagery software, and is well suited to streaming over the web or other networks.